Contained bodies of water where a person immerses himself or herself partly or wholly in the body of water can be found in swimming pools, spas, hot tubs, jetted tubs as well other containers. Generally, the person immerses his or her body partially or wholly in the body of water in order to obtain the effects of the water. In order to make the body of water safe for body contact it is necessary to kill harmful microorganisms in the water such as bacteria which can be done by dispensing antibacterial materials into the water. These types of water characteristics can be referred to as water safety characteristics. In addition, from time to time other water characteristics of the body of water, such as water comfort characteristics are adjusted. For example, the water temperature may be changed or in some cases the pH of the water may be adjusted sometimes both for safety purposes and for the comfort of the water user.
In general, a pump circulates the water in a container so as to provide a body of water with uniform water characteristics as well as to remove unwanted materials or debris from the water. During the circulation of the water dispensable materials such as minerals or other ion yielding materials can be controllable dispensed into the water through either inline dispensers or floating dispensers to control the microorganisms in the water. Other water characteristics such as a water temperature can be controlled by a heating or cooling the water as it flows through a heat transfer unit. In either case the water characteristics whether safety or comfort characteristics can be changed to make the water suitable and safe for the user.
While water characteristics in the containers have been periodically monitored and controlled by adding dispensable material to the water a feature of the invention is that the water characteristics, such as water comfort characteristics and water safety characteristics, can be monitored and controlled on-the-go. This allows the water characteristics to be maintained within close ranges which can make a users recreational experience in the water not only more comfortable but also insure that the water does not contain harmful organisms.
The invention described herein is well suited to use with small recreational water systems such as pools, spas, hot tubs or the like either as an after market item in those systems have an existing circulation system it can be introduced during the manufacture of the pools, spas, hot tubs or the like.
The concept of treating water with a source of metallic ions to kill bacteria in a body of water is known in the art. A metallic ion such as a silver ion is an effective sanitizer for a body of water including recreational water such as swimming pools, spas, jetted tubs or the like and is a preferred material because it is generally easier and safer to use than other known sanitizers. A further advantage of using silver ion as a sanitizer is that silver ion minimizes the need for pH adjustment of the body of water. However, if the concentration of metallic ions such as silver ions in a body of water is too low the ability to kill microorganisms is reduced or lost. On the other hand if the concentration of metallic ions such as silver ions is too high it can be harmful to those who use the body of water. Thus when silver ion is used as a disinfectant in a body of water one generally want to maintain the concentration of the silver ion in an effective range to kill microorganisms.
Traditionally, the sources of metallic ions used to kill bacteria in recreational water have been limited to metallic ion donors that are readily soluble in the recreational water in order to maintain an effective concentration of the sanitizers in the body of water. Silver chloride (AgCl), for example, has been a commonly used bactericide for releasing silver ions into the body of water to effectively kill microorganisms. Sodium bromide has also been known to be used with silver chloride to provide an additional and alternative water disinfection system.
In order to reduce the level of halogen in a body of water and keep the water sanitized multiple sanitizers have been used in conjunction with a halogen, for example sales literature suggests chlorine levels may be may be kept in the range of 0.5 ppm to 1 ppm if used with multiple sanitizers that include multiple metal ion sources of silver, copper and zinc. In contrast, to the afore described need for multiple sanitizers to keep the body of water in a sanitized condition when halogen levels are as low as 0.5 ppm the invention described herein allows one to use even lower levels of halogen with only a single sanitizer.
One of the problems associated with the use of silver as a sanitizer for killing microorganisms is that silver has a tendency to complex with other compounds and become increasingly insoluble thereby reducing the effective microorganisms killing ability of the silver as a sanitizer. For example, it would not be anticipated that silver chloride when used in combination with sodium bromide would be an effective disinfectant system because of the combination's tendency to form insoluble bromide crystals, which are not believed to be biologically active in aqueous environments. However, it has been discovered that if silver forms a complex with hydantoins, the silver will remain soluble to a higher degree thereby retaining the silver's antimicrobial activity.